2D-3D transition in highly strained GaAs/Ga1-xInxAs heterostructures by transmission electron microscopy

The 2D-3D transition occurring in highly strained GaAs/Ga1-xInxAs heterostructures grown by MBE was analyzed by specific TEM techniques and correlated to photoluminescence data. HREM evidences that the transition always happens in a standard growth for x similar to 0.35. This leads to a purely elastic relaxation which is characterized by a sinusoidal modulation. When the temperature is decreased, it was confirmed by ''average intensity profiles'' recorded from digitized HREM images that the transition is pushed away towards greater thicknesses. Furthermore, when adding Te as a surfactant, 311 (g, ng) weak-beam images demonstrate that the 2D growth mode is maintained up to the plastic relaxation. Finally, the change in roughness and abruptness of the interfaces is discussed as a function of growth parameters.